Cufflinks 0.8.1 released

This is a minor fix release. Cufflinks 0.8.0 had some lingering references to “RPKM”, which have been replaced with “FPKM”. Reported expression values have always been in FPKM, this is simply a nomenclature change to better reflect what RNA-Seq actually measures. See the section on FPKM in the description of how Cufflinks works